Here's a game to play for the slow hours in the office: write a story on post-it notes. Write carefully and deliberately, but do not stop, back up or edit. Grammatical errors? What a shame. Story turning out too stupid? Too bad. I've become so inured to writing on a computer screen that instantaneous, thoughtless editing has become a reflex. Writing on post-its is a way to think ahead as you write but give yourself the permission to make mistakes and do stupid shit.
Plus it looks incontrovertibly like work when people walk by your office door.
And that's why I always edit.